As a new type of display device, an organic light-emitting display device (OLED) boasts an excellent color saturation and a wide visual angle. However, since organic light-emitting materials in the OLED are sensitive to various ambient factors (such as moisture and oxygen), it is necessary to isolate the organic light-emitting materials gas-tightly from the ambient environment, and the organic light-emitting materials are generally isolated gas-tightly from the ambient environment by encapsulation.
In the prior art, the encapsulation of an organic light-emitting material is carried out as follows: firstly, forming one or more layers of the organic light-emitting material on a first substrate (comprising thin film transistors and electrodes) while forming a closed path on a second substrate with frit in the form of a paste (the area enclosed by the closed path is sufficient to accommodate the organic light-emitting material formed on the first substrate); then heating the second substrate with frit provided thereon in an oven to sinter it (also called “pre-sintering”) such that the frit is integrated with the second substrate; further then cell-aligning the first substrate with the second substrate to form a glass component, where the frit is located between the two substrates and the organic light-emitting material is located within the area enclosed by the closed path formed by the frit; finally, heating the frit in the glass component to make it soft and then cool it, thereby achieving sealing of the organic light-emitting material by using the first substrate, the second substrate and the frit.
At present, requirements for water-proof and oxygen-proof parameters of an organic light-emitting display device include: the permeability to oxygen is required to be smaller than 10-3 cc/m2/day, and the permeability to water is required to be smaller than 10-6 g/m2/day. However, a product manufactured according to a current encapsulation process can hardly satisfy the above parameter requirements. The reason lies in that, in the current encapsulation procedure, after process parameters of the encapsulation process have been set, the encapsulation will be carried out in light of the preset process parameters of the encapsulation procedure despite the actual state of the frit. In practical production, since the frit has different thicknesses at different parts of the substrate (the thickness of the frit in a marginal area is greater than that in a central area), if it is processed in light of the preset process parameters of the encapsulation procedure, part of the frit will not sufficiently melt, which may give rise to bubbles in the frit when the frit is softened and thereby influence the sealing of the product. Moreover, there may be a certain deviation of location of the frit when it is coated, and since the related process parameters have been preset during the heating and melting process, it will be inevitable that the frit in the deviation location cannot be heated and melted, resulting in degraded sealing of the product.